Chemistry and Environmental Sciences
To Burn or Not to Burn
Objective: Students learn how a locally proposed power plant may impact the
environment of their community.
National Science Education Standards:
As a result of activities in grades 9-12, students should develop
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Abilities necessary to do scientific inquiry
Understandings about science and technology
As a result of activities in grades 9-12, students should develop understanding of
Personal and community health
Environmental quality
Science and technology in local, national, and global challenges
Materials: Hand out, paper, calculator, map of Waterloo Iowa, and this website:
http://epa.gov/air/airpollutants.html . The activity should take two or more class period
to complete.
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To Burn or Not to Burn
Name:
Background: Elk Run Energy Associates, LLC (Elk Run Energy) is proposing to
construct a modern, 750-megawatt coal-fired electric generating station in Black Hawk
County. This plant will incorporate advanced emission control technology and be one of
the cleanest coal-fired plants in the U.S.
Engage: Brainstorm a list of positive and negative impacts this project could have on
Black Hawk County. Consider things like the economy, the environment and people.
Explore: You will use established emission factors to determine if the plant will exceed
the Environmental Protection Agency standards. Before we decide this however, we must
calculate the types and amounts of potential pollutants the plant may emit. This list shows
the pollutants considered harmful for human health as established by the Clean Air Act of
1990: Carbon Monoxide, Lead, Nitrogen Dioxide, Ozone, Sulfur Dioxide, and Particulate
Matter. They are collectively referred to as the NAAQS.
Open the website http://epa.gov/air/airpollutants.html
1. On a separate sheet of paper list the health concerns for each of the pollutants.
2. It has been estimated that the plant will produce 750 MW of power each day.
To do this, the plant will need to burn coal at the rate of 2900 tons/day. At this rate
however, the efficiency of converting that to electricity is only about 33%. How much
coal will need to be consumed to produce all 750 MW?
3. If one rail car holds 100 tons of coal, how many rail cars will be needed daily to supply
the plant with a sufficient amount of coal?
4. Calculate the amount of emissions per day for each of the pollutants listed in the EPA
report from question #1 using the emission factors below. The emissions can be found by
multiplying the activity rate in tons per day, times the emissions factor. Assume that there
is no control to reduce the emissions. The basic formula for calculating emissions is: E =
A x EF x (1-ER/100)
where:
E = emissions;
A = activity rate;
EF = emission factor
and ER = overall emission reduction efficiency, %
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The following activity rates are per ton of coal.
SO2 – 52.5 lb/ton
NO2 – 7.4 lb/ton
CO – 0.5 lb/ton
PM (Particulate Matter) - 100lb/ton
Explain: Many citizens have expressed health concerns regarding the emissions from
this plant. The company claims that it will be one of the cleanest power plants in the U.S.
The chart below indicates the EPA’s air quality standards that must be met by the power
plant.
National Ambient Air Quality Standards
Pollutant
Carbon Monoxide
Primary Stds.
9 ppm
(10 mg/m3)
35 ppm
(40 mg/m3)
Lead
1.5 µg/m3
Nitrogen Dioxide
0.053 ppm
(100 µg/m3)
Particulate Matter (PM10) Revoked(2)
150 µg/m3
Particulate Matter (PM2.5) 15.0 µg/m3
35 µg/m3
Ozone
0.08 ppm
0.12 ppm
Sulfur Oxides
0.03 ppm
0.14 ppm
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Averaging Times
8-hour(1)
Secondary Stds.
None
1-hour(1)
None
Quarterly Average
Annual (Arithmetic Mean)
Same as Primary
Same as Primary
Annual(2) (Arith. Mean)
24-hour(3)
Annual(4) (Arith. Mean)
24-hour(5)
8-hour(6)
1-hour(7)
(Applies only in limited areas)
Annual (Arith. Mean)
24-hour(1)
3-hour(1)
Same as Primary
Same as Primary
Same as Primary
------------0.5 ppm
(1300 µg/m3)
5. What is a ppm? How large is a cubic meter (m3)? What is a µg?
6. When you look at your results from the calculations above, what do you notice
regarding the expected emissions?
7. What must be missing? What is needed for the proposed plant to comply with the
guidelines set forth by the EPA?
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Elaborate: On your map, plot the location of the proposed plant.
8. Which direction is north? Place a compass rose on the bottom corner of your map.
9. Where do you live? Plot the location of your home on the map.
10. Generally speaking, what wind direction is most prevalent in the Midwest?
11. What wind direction would guide the smoke plume from the plant towards your
home?
12. Is there a reason for citizens to be concerned?
13. What kinds of things would you want to ask the representatives from the power
company?
Evaluate: There should be six major pollutants listed and the health concerns for each.
The teacher should evaluate the responses to the calculations. The map should be labeled
correctly and responses to the questions should reflect the answers from the stated
problems.
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Assessment Rubric:
CATEGORY
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Calculations
All calculations are
shown and the results
are correct and labeled
appropriately.
Some calculations are Some calculations are
shown and the results shown and the results
are correct and labeled labeled appropriately.
appropriately.
No calculations are
shown OR results are
inaccurate or
mislabeled.
Participation
Used time well in lab
and focused attention
on the experiment.
Used time pretty well.
Stayed focused on the
experiment most of the
time.
Did the lab but did not
appear very interested.
Focus was lost on
several occasions.
Participation was
minimal OR student
was hostile about
participating.
Question/Purpose
The purpose of the lab
or the question to be
answered during the
lab is clearly identified
and stated.
The purpose of the lab
or the question to be
answered during the
lab is identified, but is
stated in a somewhat
unclear manner.
The purpose of the lab
or the question to be
answered during the
lab is partially
identified, and is stated
in a somewhat unclear
manner.
The purpose of the lab
or the question to be
answered during the
lab is erroneous or
irrelevant.
Summary
Summary describes the
skills learned, the
information learned
and some future
applications to real life
situations.
Summary describes the Summary describes the No summary is
information learned
information learned.
written.
and a possible
application to a real
life situation.
Data
Professional looking
and accurate
representation of the
data in tables and/or
graphs. Graphs and
tables are labeled and
titled.
Accurate
representation of the
data in tables and/or
graphs. Graphs and
tables are labeled and
titled.
Accurate
Data are not shown
representation of the
OR are inaccurate.
data in written form,
but no graphs or tables
are presented.
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Teacher Notes:
Health Effects of Lead
Exposure to lead can occur from breathing contaminated workplace air or house dust or
eating lead-based paint chips or contaminated dirt. Lead is a very toxic element, causing
a variety of effects at low dose levels. Brain damage, kidney damage, and
gastrointestinal distress are seen from acute (short-term) exposure to high levels of lead
in humans. Chronic (long-term) exposure to lead in humans results in effects on the
blood, central nervous system (CNS), blood pressure, kidneys, and Vitamin D
metabolism. Reproductive effects, such as decreased sperm count in men and
spontaneous abortions in women, have been associated with high lead exposure. The
developing fetus is at particular risk from maternal lead exposure, with low birth weight
and slowed postnatal neurobehavioral development noted. Human studies are
inconclusive regarding lead exposure and cancer.
Health Effects of Particulate Matter
The size of particles is directly linked to their potential for causing health problems. EPA
is concerned about particles that are 10 micrometers in diameter or smaller because those
are the particles that generally pass through the throat and nose and enter the lungs. Once
inhaled, these particles can affect the heart and lungs and cause serious health effects.
EPA groups particle pollution into two categories:
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"Inhalable coarse particles," such as those found near roadways and dusty
industries, are larger than 2.5 micrometers and smaller than 10 micrometers in
diameter.
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"Fine particles," such as those found in smoke and haze, are 2.5 micrometers in
diameter and smaller. These particles can be directly emitted from sources such as
forest fires, or they can form when gases emitted from power plants, industries
and automobiles react in the air.
Health Effects of Nitrogen Dioxide
NOx reacts with ammonia, moisture, and other compounds to form nitric acid and
related particles. Human health concerns include effects on breathing and the respiratory
system, damage to lung tissue, and premature death. Small particles penetrate deeply into
sensitive parts of the lungs and can cause or worsen respiratory disease such as
emphysema and bronchitis, and aggravate existing heart disease.
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Health Effects Associated with Carbon Monoxide
At low concentrations, fatigue in healthy people and chest pain in people with heart
disease. At higher concentrations, impaired vision and coordination; headaches;
dizziness; confusion; nausea. Can cause flu-like symptoms that clear up after leaving
home. Fatal at very high concentrations. Acute effects are due to the formation of
carboxyhemoglobin in the blood, which inhibits oxygen intake. At moderate
concentrations, angina, impaired vision, and reduced brain function may result. At higher
concentrations, CO exposure can be fatal.
Health Effects of Ozone
People with lung disease, children, older adults, and people who are active can be
affected when ozone levels are unhealthy. Numerous scientific studies have linked
ground-level ozone exposure to a variety of problems, including:
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lung irritation that can cause inflammation much like a sunburn;
wheezing, coughing, pain when taking a deep breathe, and breathing difficulties
during exercise or outdoor activities;
permanent lung damage to those with repeated exposure to ozone pollution; and
aggravated asthma, reduced lung capacity, and increased susceptibility to
respiratory illnesses like pneumonia and bronchitis.
Health Effects of Sulfur Dioxides
SOx contributes to respiratory illness, particularly in children and the elderly. It may also
aggravate existing heart and lung diseases. People with asthma are particularly affected
by high levels of SO2.
Emissions Calculations
SOx
E = 8700tons/day x 52.5 lb/ton = 456,750 lb/day
NOx
E = 8700 ton/day x 7.4 lb/ton = 64,380 lb/day
CO
E = 8700 ton/day x 0.5 lb/ton = 4350 lb/day
PM
E = 8700 ton/day x 100lb/ton = 870,000 lb/day
Some students will need assistance with the terms and the math. Students should see that
the emissions from such a large plant are going to enormous. However, the portion of the
emissions equation that is missing are the technological controls that are intended to
reduce the emissions to meet EPA standards. Answers to the questions should reflect this.
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